Mechanisms Of Trappc8 And Rab26 Participating In Autophagy

Autophagy is a process in which cells process their own proteins and organelles by phagocytosis.It plays an important role in maintaining intracellular environmental stability and material energy reuse.Autophagosome encapsulates phagocytic substances through a bilayer membrane structure which have a wide range of sources,such as endoplasmic reticulum,Golgi apparatus and endosomes.Many members of the Rab protein family and transporter protein particle(TRAPP)complex family involved in the intercellular vesicle transport also participate in the autophagic process.Rab26 was screened as a candidate protein when we studied the interaction protein of Trappc8 in the early research.Previous studies have shown that Trappc8 participates in the transport of ATG9,a key protein of autophagy formation,while Rab26 also participates in autophagy,but the mechanism is not clear.Therefore,this study further explores the mechanism of Trappc8 and Rab26 participating in autophagy.The main results are as follows:(1)Co-Immunoprecipitation(Co-IP)method confirmed the interaction between Rab26 and Trappc8;(2)RNA interference knockdown of Trappc8 changed the distribution of Rab26 in cells;(3)RNA interference knockdown of Rab26 resulted in accumulation of autophagosomes in cells,and this phenomenon was caused by the obstacle of fusion between autophagosomes and lysosomes;(4)Overexpression of Rab26 promotes the clearance of autophagosome by cells.(5)RNA interference knocking down Trappc8 also leads to the dysfunction of fusion between autophagosomes and lysosomes.Above results suggest that Rab26 interacts with Trappc8,which regulates intracellular localization of Rab26.Rab26 mediates fusion of lysosomes and autophagosomes during autophagy.Trappc8 not only participates in the formation of autophagosomes in the early stage of autophagy,but also in the fusion of autophagosomes and lysosomes in the late stage of autophagy,which may be achieved by regulating the activity of Rab26.In order to study the regulation mechanism of Trappc8 and Rab26 on autophagy-related pathways,we tried to establish a mechanism of Trappc8 participating in the fusion of autophagosome and lysosome in late autophagy by regulating Rab26.